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Friction comb section 49-09

redmark

Active Member
FYI: Those who received FF kits spring 2010 will not have the friction comb FF-00002 needed in section 49-09 rev. 2. I contacted Van's here is their reply.

-Ron

"It was not missing - we had not made the parts then, and it is not on your inventory list. They will be sent out later."

vans
 
Thanks! We just unpacked that part last night during inventory and was wondering what the heck that was, since it wasn't on the inventory list.

Our inventory list was pretty messed up, the bag versions were way off on quite a few.
 
Too much friction with friction comb

I just installed the heater door cable and noticed, that I have way too much friction when inserting the F-120002 friction comb part.
Opening and closing the door works very well without that part and I am happy with the installation. The cable is routed according to KAI and no obvious issues are encountered.
I am asking if in this case I should omit the comb or maybe just using 2 of the 3 notches.
Has anyone experienced the same?
Thanks a lot for your input on that.
 
Chris - Yes, the comb does add a large amount of friction.

Admittedly, I have not yet played with the cabin heat while in flight. (All my flight days thus far have been warm). However, I suspect the additional friction offered by the comb may come in handy during flight when there is a significant amount of air pressure on the heater door ... especially when attempting to hold a position between fully open and fully closed.

Happy building,

John
 
My heater cable was impossible to pull with all 3 notches. Reduced to 2 and still too hard. It's been a while, but if I remember correctly, I'm now at 0 notches. Admittedly, it doesn't get much use here in FL but do need it when flying north ...
 
If you have too much friction you could also bend the comb a little to put less bend in the cable. Instead of a completely flat comb and all the bends in the cable, or a completely straight cable with no comb, put a slight bend in the comb so the cable is slightly less bent.
 
I tossed mine after I got the AW certificate. The heater door works fine without it on my 12.

Thanks for the info Rich .... that is good to know. If that's the case, may toss my comb as well because it certainly adds A LOT of friction.
 
I tossed mine after I got the AW certificate. The heater door works fine without it on my 12.
The other side of the coin... mine fell off during the condition inspection last year, and I didn't put it back on. Now my heater has two positions: fully closed, and and fully open. Any time it's open more than about 3/8" it will quickly get opened all the way. This year I'm making a new friction comb and putting it back on.
 
I just installed the heater door cable and noticed, that I have way too much friction when inserting the F-120002 friction comb part.
Opening and closing the door works very well without that part and I am happy with the installation. The cable is routed according to KAI and no obvious issues are encountered.
I am asking if in this case I should omit the comb or maybe just using 2 of the 3 notches.
Has anyone experienced the same?
Thanks a lot for your input on that.

One more data point. I thought the heater control was very hard to position during the build. However, in flight it is easy to set, and stays where I put it. Important when you live in Wisconsin! You might consider building per plans, and if it's still too tight in flight, modify then.
 
If that's the case, may toss my comb as well because it certainly adds A LOT of friction.

Visually look at what the comb is doing to add friction......

It causes a zig-zag of the cable which increases the slide friction.

If after installation (and test flying) you think the friction is too high, gently bend the comb a bit to reduce the amount of zig and zag.
As would be expected, this will cause a reduction in the amount of friction.
Adjust to your liking, but as already mentioned, the dynamic pressure on the door is pretty high in the middle of the adjustment range so it takes quite a bit of friction to keep in the position you select.
 
Thanks a lot for all of your thoughts. That confirms me that I am on track and that I haven't done a mistake in installing that cable.
Eventually I will install the comb with a slightly larger radius (bending it) and considering to secure it with safety wire around the cable.
Chris
 
Mine stays put at whatever position I set without the comb. I did add a 1/2" angle along the firewall where the edge of the heater door meets the firewall to improve the seal when heat is off.
 
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